In this latest intellectual biography of William Penn, Andrew R. Murphy draws on his exploration of the relationship between Penn's tolerationist writings and his political engagement to argue for his greater inclusion in the canon of early modern political theory. Murphy explicitly presents his study as a response to the methodological challenge of the Cambridge School, and the recent renewal of scholarly interest in the Restoration era and the Atlantic world. He argues that Penn's significance is obscured by the ‘twists and turns of his political career’, and yet he ‘possesses all the hallmarks of a political theorist as most scholars would understand the term’. In this sense, Liberty, conscience and toleration points beyond the mere study of Penn as an individual, to propose a fundamental reconfiguration of how the canon – and indeed, theory itself – is understood.

The work navigates Penn's life through a series of broadly chronological case studies. Having outlined his methodological approach in chapter i, chapters ii and iii consider Penn's emergence onto the public stage as both a political thinker and actor. In Penn's 1670 The great case of liberty of conscience – ‘probably the most elaborate and systematic theoretical writing on toleration Penn ever produced’ – Murphy identifies conceptual elements of Penn's tolerationism that would remain prominent throughout his career, as they were forged during the preparation and passage of the Second Conventicle Act. Turning then to consider Penn's trial alongside William Mead, Murphy emphasises his appeal to ‘embedded principles’, his employment of ‘performative politics’ in the trial itself, and (drawing on the conceptual framework of Gilles Deleuze) the ‘dramatisation’ of the political through the publication of a transcript of the trial. Murphy identifies Penn's influence in producing that transcript, which he presents as a work of ‘political theory as political theatre’. To this end, Penn's primary significance is found not in the originality of his ideas, but in his ability to perform and embody the arguments of the wider tolerationist movement.

This almost rhetorical relationship between theory and practice is elaborated further in the following chapters. Chapter iv examines Penn's activities during the Popish Plot and Exclusion Crisis, focusing on his understanding of the role of parliament and the nature of popery. In chapter v Murphy considers the foundation of Pennsylvania, during which Penn enjoyed his fullest opportunity to enact his political vision. Chapter vi considers Penn's activities in the prelude to the Glorious Revolution, suggesting a greater degree of consistency than most scholars allow between his earlier views and later support for James ii. Chapter vii examines the troubles facing Pennsylvania in the 1690s (most notably, the Keithian controversy), Penn's essay forwarding a scheme for peace in Europe, and the implications of his later return to Pennsylvania. Finally, in chapter viii, Murphy considers what can be said of Penn's legacy. To this end, he notes that many elements of ‘legacy’ ordinarily associated with Penn can be separated from the legacy of Penn himself; for example, the success of Pennsylvania might even have been due to Penn's absence from the colony. None the less, Penn remains significant for his intimate involvement in ‘both the theorizing and the practice of politics’ – indeed, as colonial founder he was involved at a qualitatively different level from that of other early modern political theorists – which Murphy argues makes him worthy of much greater scholarly attention.

In the first instance, Murphy's study makes a valuable contribution as a close dissection of Penn's central beliefs, influences and motivations throughout his career. Yet more than this, the work raises pertinent questions regarding the interaction of, and distinction between, ‘theoretical’ and ‘practical’ spheres. Murphy diagnoses a continual flow between theory and practice – and his exhortation for greater scholarly consideration of Penn is largely grounded in his revised vision of what a ‘theorist’ must look like. Whether through Penn's dramatic appearance in court, his practical advice to voters alongside reflections on the fundamental role of the Commons during the Exclusion Crisis, or his attempt to establish a workable political framework in Pennsylvania, his political theory was constantly defined and guided by both the practical and the performative. This concern is most explicit in Murphy's discussion of Penn's colonial activities, in which he seeks to nuance the understanding of this episode as an attempt to translate theory into practice, by suggesting a complex relationship of ‘mutual interconnections’ between theory and practice. The political reality of Pennsylvania was significantly informed by Penn's political theorising in the previous decades, but that theory also continued to be shaped by the consolidation of government in the colony throughout Penn's life. These adjustments did not simply reflect shortcomings in Penn's theory, but were symptomatic of the ‘indeterminate and contested’ nature of the ‘phenomena of which theory is constituted’ – that is, the inevitable ‘flux at the very heart of politics’.

Clearly, Murphy's primary audience is in political science. However, especially given his explicit concern for the fuller contextualisation of Penn's thought, his work would have benefitted from greater consideration of the impact of Penn's theology on that thought. For example, regarding Penn's argument that genuine faith could never be the result of coercion, Murphy stresses that he was exhorting ‘mature understanding and deliberate consideration’. Yet Penn's belief in what he termed the ‘self evidenceing [sic] verity’ of Christianity (Great case, 11) fundamentally arose out of his belief in the immediate guidance of the inward Light of Christ, and was articulated in the context of a wider theological dispute regarding the Quakers’ commitment to the necessity of belief in the historical Jesus. Similarly, Penn's emphasis on high moral standards and his understanding of conscience in terms of duty towards God, alongside his minimalist approach to the basic doctrinal requirements for toleration, echo Quaker demands for obedience to the Light and the believer's potential for sanctification. What effect did Penn's theology have on his navigation between ideological and pragmatic commitments?

However, this should not detract from Murphy's contribution. His interrogation of assumptions regarding canonicity, and his refusal to draw clear lines between Penn's life, performance and ideas, are relevant far beyond the realm of political science – and to this end his work will undoubtedly have a captive readership among students of early Quakerism, the broader tolerationist movement, colonial and transatlantic history, and the religious and political milieus of the later seventeenth century.